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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2015-03-09 23:11:12 +0200 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-03-28 10:03:28 -0400 |
| commit | 1cd3d374b25ba7e9934be66781ff7fc4513a2b09 (patch) | |
| tree | 78ca0d8a9db61fdadcf35ae9cd4519b9e18b74ee | |
| parent | 016958bf0577daa731bf0fc84aaa8a47d2dd705d (diff) | |
| download | lwn-1cd3d374b25ba7e9934be66781ff7fc4513a2b09.tar.gz lwn-1cd3d374b25ba7e9934be66781ff7fc4513a2b09.zip | |
pagemap: do not leak physical addresses to non-privileged userspace
[ Upstream commit ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce ]
As pointed by recent post[1] on exploiting DRAM physical imperfection,
/proc/PID/pagemap exposes sensitive information which can be used to do
attacks.
This disallows anybody without CAP_SYS_ADMIN to read the pagemap.
[1] http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html
[ Eventually we might want to do anything more finegrained, but for now
this is the simple model. - Linus ]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Seaborn <mseaborn@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
| -rw-r--r-- | fs/proc/task_mmu.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index e8972bcddfb4..69aa378e60d9 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1291,6 +1291,9 @@ out: static int pagemap_open(struct inode *inode, struct file *file) { + /* do not disclose physical addresses: attack vector */ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about " "to stop being page-shift some time soon. See the " "linux/Documentation/vm/pagemap.txt for details.\n"); |